Sanding machine



W. L. PETERSEN Feb. 14, 1950 SANDING MACHINE 3 Shets-Sheet 1 Filed April 12, 1948 Millie/m J. -E92 2;1942/1;

X 1" I I J/y/eey.

Feb. 14, 1950 w, PETERSEN 2,497,791

SANDING MACHINE Filed April 12, 1948 3 Sheets-Sheet 3 Patented Feb. 14, 1950 SANDING MACHINE William L. Petersen, West New York, N. J., as-

signor to Clarke Sanding Machine Company, Muskegon, Mich., a corporation of Michigan Application April 12, 1948, Serial N0. 20,389

6 Claims. 1

The present invention relates to sanding machines and particularly to heavy-duty floor sanders of the drum type.

In machines of this general type, it is obviously of advantage to utilize a large sanding drum operating at a high speed of rotation, in order to per mit a high cutting rate and thus make the speed of operation as fast as possible. It has long been a problem, however, to provide a satisfactory contro1 mechanism for such a machine, since while extremely high cutting speeds are desirable, if properly controlled, yet if the control mechanisms are not smooth acting, positive and precise fast cutting machines can easily cut or groove a floor surface so deeply as to cause serious damage.

The problems incident to control of a highspeed sanding drum in a portable machine are by no means new; in fact, they have vexed workers in this field for many years. Many efforts have been made to provide improved control devices, but despite the time and effort that have been spent, no completely successful solution has heretofore been forthcoming.

It is accordingly the primary object of the present invention to provide, in a portable sanding machine, a large high-speed heavy-duty motor-driven sanding drum, together with a machine carriage having its parts so related and constructed as to permit free and easy many movements of the machine across the floor surface and, at the same time, accomplish smooth, precise and positive manual control of the cutting depth, and permit quick and accurate leveling adjustment.

It is a further object of the invention to provide a carriage for a drum type sanding machine, wherein accurate leveling and precise control of the cutting depth of the sanding drum are achieved, yet wherein the several parts are so constructed and related as to permit the utilization of an efficient dust collecting system, including a suction nozzle extending across the entire width of the drum near its cutting surface.

The foregoing objects are accomplished according to the present teaching by providing a machine including a relatively large and heavy main casting on which the sanding drum, motor and a suction fan are mounted, with the casting comprising a tricyclecarriage having a single caster wheel atthe end of the machine remote from the drum, and a pair of vertically shiftable spring balanced leveling wheels on opposite sides of the machine near the cutting surface. A preferred commercial embodiment of the principles of this invention is illustrated in the drawings of this specification, in which:

Figure 1 is a side elevational view of a sanding machine constructed in accordance with the present teachings;

Figure 2 is a plan view thereof;

Figure 3 is a detail sectional View taken substantially on the plane of the line 33 of Figure 1;

Figure 4 is a bottom plan view of the machine; and

Figure 5 is a detail sectional view taken substantiall on the plane of the line 5-5 of Figure 1.

The machine comprises, in its general structure, a main frame casting I 0 having downwardly extending side flanges ll along both sides and around the rear end, with a rotatable sanding drum 12 carried at the forward end. The drum I2 is mounted on a shaft I3 extending between bearings It in the opposite side flanges II, and is driven by the motor I5. The motor is connected to the drum through a pair of belts l6 enclosed in a guard or housing [1.

The main casting i0 is formed to include an arcuately shaped rear wall l8 extending around the upper and back portion of the drum, and a pivoted front cover 19 is secured to the frame so that it will normally enclose and act as a guard for the forward portion of the drum, but may be hinged upwardly on the pivot 2| to permit access to the drum for replacing the abrasive paper 22. The motor l5 also drives a centrifugal suction fan 23 by means of the belt 24. The suction fan is enclosed in a fan housing 25, and forms part of a dust collecting system. The suction side of the dust collecting system consists of a wide nozzle '21, positioned immediately behind the cutting surface of the drum l2, and extending the full width of the drum. The nozzle 21 has a neck portion 28 extending rearwardly and terminating in a flat plate 29, which forms the forward Wall of the fan housing 25. The plate 29 has notches in its edges coacting with the lugs 3! I to hold the nozzle in position, but arranged to permit release of the nozzle and neck by rotary movement of the plate with respect to the housing, Thus,-the fan 23 acts to draw the dust inwardly at its center and discharges it through the exhaust pipe 26 to any suitable dust bag (not shown).

The nozzle 21 is positioned immediately above the surface of the floor at a point just behind the cutting surface of the drum, and is carried on an adjusting stud 34 threaded into a center boss 35 in a cross flange 36 of the main frame to maintain the nozzle in the precise vertical position desired. A lock. nut 37 is placed on the stud to prevent it from working loose, and a spring clip 32 is provided on the nozzle to snap over the roundedlhead 13.v of the stud 34. so that the nozzle may beremovedand replaced without altering the adjustment.

The machine carriage, to which the present invention is particularly directed includes, -ztogether with the frame casting, a single caster wheel 38 mounted on a vertical swivel 39- at-the back end of the machine, together with a-pair of leveling wheels 4!, each carried b thelower forked end 42 of a vertical stud 43. 43 slidably mounted in bearing sleeves 44, fitted in the hubs 45 of the machine frame. and manuall controlled tensioning devices are provided '--to balance thexweight: of the "machine andlthus hold the drumxlevel vrand :in "properpressure" en- :gagement with' the-work. To this end the: rear 1 sidewall. of the hub -45 and bearing sleeve '44 are slotted; as 1 indicated at 46, so that the rounded head portion 41 of an arm 48 may. extend through each or the. slotsand engage the studs 43 between the upper and lower curvedsurfaces of across slot 49.

Y and convenient manually adjustable tension setting for this spring and to this end the split sleeve 69 is provided with a screw thread p012 tion 1'5, on which a thread adjusting collar 1'! is mounted. The upper extremity of the collar is grooved at I8 to receive the opposite ear portion of a shiftable washer 8!. The washer BI is slotted at 82 to surround the pull rod 64, but the ear portions 19 project through opposite slots 83 in the side walls of the tubular handle Bl, so that as the sleeve l! is manually rotated on the thread 16 the washer will be correspondingly raised or lowered :tonefiect :a precise ad- 'justment' of the spring 13.

The pull rod 84 extends on up the handle to a more or less conventional hand lever control, \-.which is not shown in the drawings but which serves to raise or lower the rod 64 in response to manual'manipulation by the operator.

The studs: are I The arms 48 include enlarged bearingfibosses' "or hubs -50; individually pivoted'on a crossrod 5l extending between the:oppositefsidexflanges 1 H of -the machine. The icross rod is amounted in bosses 52 on the flanges, and is secured in "fixed position-"by the -s'et screws 53. 'f The arms 48' are thus individually free "to pivot, but their downward "movement, and consequently "the "downward movement of" the leveling wheels? 4|, is limited by' a pair of -stop' screws 54, *each ilthrea'ded through a lug '55 projeeting outwardly '7 from the lower" ends of "the bosses 45.

Theistop rscrews are provided with locking'nuts 56 to secure them in' any'desired position of adjustment.

The arms- 48 i are actuated -by an operating lever 51 common-td-both of thearms, andin'the preferred construotion ,'the arms 5711s .formed with 't'a pair of integral"'bearing"portions' id, immediately a'djacentthe hubs 'dfipf the levers' i'a and interconnected by a'semicircular flange 59. The

bearings 58- each *carryan arm' 6l,"curving for- "ience' ma be mounted on? a" handle bracket '68,

and secured in positionina'spllt sleeve 69 having ".a pair'of clamping'lugs It adapted to me-drawn .1 normally'urged upwardly by a-c'oiled' compression -spring 1.3, which-surrounds the rod *and bears against: a collar 74, fixed to" the s rod by the pin ZT'I5 to zurge'r the rod in: an upward direction.

" Itis desirable to provide an I easily accessible The pull rod'fitl extends upwardly In operation, it will be seen that the greater part of'the'weight of the machine is carried on theoppositerleveling rollers 4|, which may be adjusted to precisely level relationship with re- .spectto'the drum I2 by manipulation of the set screws 62 and locking vnuts 63. In practice one of these is-set atavpermanent: adjustment at the factorygand'Ithes'leveling adjustment effected by either raising or lowering the other: screw; 'asnre- "quired. Thisisconvenientlysdone at any time necessary, since "an'aperture fidis: cast inthe 'side -wallof onecof the. flanges H toprovide'easy aceessto theliscrew and its 'lockingnut. Downwvardly spring pressure is applied to each of the vertical Islide studs 1 A3 1 by the levers 48,- which are in turn' spring'urgedsby" the "spring 13, acting through the pull rod 54.-fclevis' G5,. operat- :ing lever 57 anda'arms -6|. Therelative a-djustment of =the screws 62 @between the: arms 6! and levers 43 provide ajoonstantly equal spring. :force on eachof the rollersj'so' that: theesandingzdrum will remain exactly .level; at "ithezsaine time, the 'total' forcezexerted by -the spring may i-be: conven- 'iently' adjusted by. manually rotating the sleeve 11, -so that the force a'exerted" by? the spring 13 balancestheweight' of the machine to'the exact degree desired. "It follows .that as" theimachine is-"moved across the floor the cutting'depth of the sanding drum mayThe:preciselycontrolled -by theoperatorbymanipulation :of 'a "handle lever to raise 'or lower the pull "rod' lid The swivelingmovement of the caster 3Bpermits the "machine'to be easily 'guidedin-any desired :di-

rection, yet the' fact that the leveling wheels 4 I do not swivel nor-move in any direction, other "than "in an exactly vertical pa'th; means that :the difficulties or alignment "ofprior typesof machines are' larg'ely over-comexan'd that the -"dangers of excessively cutting or grooving the floor due to improper control of the cutting speed of the drum are successfully overcome.

This object-is brought about "by the use of a wheel'moun'ting and adjusting construction that provides an extremely rugged *and sturdy support 'for'the leveling wheels-M, so thatthey are "not apt" tobe misaligned by-accidental impact or 'shockincident to moving the machine 'over irregular surfaces; and sinceeach wheel is supported with the center of the *wheel "directly under the center of the vertically 'slidable stud.

"with'the' result that" an unusually highdegree' of 'rigiditybfthe structure is':obtaine'd"wlthout "unnecessarystrength "or' bulk or the machine "parts. 'iThe"relatively*longlsliding .stlld t3 pro- 'vides a smoothly functioning vertical adjusttcmentsand a-tfthe sametime provides-1a nonstruction characterized by freedom from looseness. chatter, play or vibration, so that precise leveling is accomplished without the sacrifice of other features of importance in the machine structure.

While the form of the invention illustrated in the drawings and described herein is the preferred commercial embodiment of these teachings and is believed to be particularly well suited to a description of the advantages inherent therein, it is to be recognized that various deviations in the exact construction and arrangement of parts may be made without departing from the teachings of this disclosure, and it is accordingly pointed out that the precise structure described is referred to by way of illustration rather than by limitation, and that the scope of the inventive concept of this disclosure extends equally to any variation or modification of structure coming within the terms of the appended claims.

Having thus described the invention, what I claim as new and desire to protect by United States Letters Patent is:

1. In a sanding machine including a motordriven sanding drum adapted to rotate on a generally horizontal axis and to act against the surface on which the machine is supported, the combination of drum supporting devices including a single swiveled caster wheel, remote from and at right angles to the axis of rotation of the drum; together with a pair of individually operable vertical slides adjacent the drum near its opposite ends; and a leveling wheel carried at the lower end of each of said slides, together with a pivot shaft extending across the machine adjacent the slides, and a pair of levers freely pivoted on the shaft near its opposite ends with each of the levers engaging one of the slides, a leveling fitting pivoted on the pivot shaft between the levers, with means on the leveling fitting to operatively engage both levers, said means comprising screw threaded adjusting means to adjust the relative positions of the levers and slides and effect precise leveling of the sanding drum on the floor surface; together with a spring tensioning device acting on the leveling fitting and common to each of said slides, including an actuating rod extending upwardly from the leveling fitting through the machine handle, a coil spring within the handle and surrounding said rod, a screw threaded sleeve surrounding the handle, and means interconnecting the spring and the sleeve to adjust the spring by manual rotation of the sleeve.

2. In a sanding machine including a motordriven sanding drum adapted to rotate on a generally horizontal axis and to act against the surface on which the machine is supported, the combination of drum supporting devices including a single swiveled caster wheel, remote from and at right angles to the axis of rotation of the drum; together with a pair of individually operable vertical slides adjacent the drum near its opposite ends; and a leveling wheel carried at the lower end of each of said slides, together with a pivot shaft extending across the machine adjacent the slides, and a pair of levers pivoted on the shaft near its opposite ends with each of the levers engaging one of the slides; screw threaded adjusting means to adjust the relative positions of the levers and slides and effect precise leveling of the sanding drum on the floor surface; together with a, spring tensioning device common to each of said slides, including a manually operable actuating rod extending upwardly through the machine handle, a coil spring within the handle and surrounding said rod, a screw threaded sleeve surrounding the handle, and means interconnecting the spring and the sleeve to adjust the spring by manual rotation of the sleeve.

3. In a sandingmachine including a motordriven sanding drum adapted to rotate on a generally horizontal axis and to act against the surface on which the machine is supported, the combination of drum supporting devices ineluding a single swiveled caster wheel, remote from and at right angles to the axis of rotation of the drum; together with a pair of individually operable vertical slides adjacent the drum near its opposite ends; a leveling wheel carried at the lower end of each of said slides and spring means for urging of said slides downwardly to at least partially balance the weight of the machine on said leveling wheels, together with a pivot shaft extending across the machine adjacent the slides, a pair of levers on the shaft near its opposite ends with each of the levers engaging one of the slides, and screw threaded adjusting means to adjust the relative positions of the levers and slides and effect precise leveling of the sanding drum on the floor surface.

4. In a sanding machine including a frame and handle, with vertically shiftable wheels in the frame and a manually operable wheel control rod extending through the handle; the combination of spring balancing devices including a coiled compression spring surrounding the control rod in the handle; a collar fixed to the rod at the upper end of the spring whereby the spring may urge the rod upwardly; a pair of vertically extending slots in the tubular handle adjacent the lower end of the spring; with a spring seat comprising a washer surrounding the rod at the lower end of the spring and adapted to support the spring, with a pair of lugs on said washer extending through the slots in the handle and a screw threaded collar on the outside of the handle engaging the lugs of said washer; the collar including a manual grip portion whereby it may be threaded up or down in order that the tension of the spring may be adjusted by manual rotation of the sleeve.

5. In a sanding machine including a motordriven sanding drum adapted to rotate on a generally horizontal axis and to act against the surface on which the machine is supported, with drum supporting devices including a single swiveled caster wheel, remote from and at right angles to the axis of rotation of the drum; together with a pair of leveling wheels, means for urging of said leveling wheels downwardly to at least partially balance the weight of the machine on said leveling wheels, a tubular handle on the machine anda wheel control rod for shifting said leveling wheels, said control rod extending through said handle; the combination of spring means including a coiled compression spring positioned within the handle and surrounding the control rod extending therethrough, a collar fixed to the control rod and engaged by one end of the spring, and a shiftable spring support for one end of the spring, said support having at least one lug extending through a slot in the handle, and a screw threaded sleeve outside of the handle engaging said lug to move the shiftable spring support longitudinally of the rod and adjust the spring by rotation of the sleeve.

6. The combination, with a control rod and handle, of spring means including a coiled com- 75 pression spring positioned within the handle and 

